激光熔覆原位自生TiC颗粒增强镍基复合涂层的组织与耐磨性

采用预置粉末法在45钢表面进行激光熔覆镍基Ni60A+x%(SiC+Ti)(质量分数,下同)复合粉末涂层的实验研究。使用往复式磨损试验机对不同涂层材料的熔覆层进行干摩擦磨损实验,利用金相显微镜、扫描电镜(SEM)观察和分析熔覆层的显微组织与磨损形貌。结果表明:复合粉末通过原位反应生成弥散分布的TiC颗粒增强复合涂层,随着(SiC+Ti)含量的增加,颗粒状TiC的尺寸和数目逐渐增加;复合粉(SiC+Ti)含量达到60%时,微观组织有气孔和夹杂缺陷;复合粉(SiC+Ti)含量为48%时,熔覆层耐磨性最佳;复合涂层的磨损主要为磨粒磨损,机理为微观切削和挤压剥落。

Microstructure and Abrasion Resistance of In-situ TiC Particles Reinforced Ni-based Composite Coatings by Laser Cladding

Laser cladding of Ni-based Ni60A+x% (SiC+Ti)(mass fraction,the same below) composite powder coating on 45 steel substrate was studied by using the method of preplaced powder.The dry friction and wear experiments of different material coatings were carried out by reciprocating friction wear tester.The microstructure and worn morphology of cladding layers were observed and analyzed by using metallographic microscope, scanning electron microscope(SEM) respectively.The results show that the prepared composite coating with dispersively distributed TiC enhanced particles are obtained in-situ, the size and number of the granular TiC gradually increase with the increase of the composite powder SiC+Ti.When the composite powder SiC+Ti reaches 60%, pores and inclusions defects exist in microstructure.When the composite powder SiC+Ti reaches 48%, wear resistance of cladding coating is the best.The wear behavior of the composite coating is abrasive wear, and the mechanism is micro cutting and extrusion spalling.